Are these intents only open to Siri? If so, and if security is the cause: on Android, apps have the option of looking up the app triggering an intent of theirs

Are these intents only open to Siri? If so, and if security is the cause: on Android, apps have the option of looking up the app triggering an intent of theirs to check its APK signature in order to verify the origin (allows for secure inter-app communication).